The present invention relates to a method of producing filter-tipped cigarettes.
As described, for example, in British Patent N. 2,241,866, filter-tipped cigarettes are known to be produced on a filter assembly machine defining, internally, a path along which elongated tobacco items are fed transversely in relation to their axis. The input of the above known filter assembly machine is supplied with a succession of first tobacco items consisting of double cigarette portions, which, as they are fed transversely along said path and through a cutting station, are each cut into two single portions forming a first and second orderly succession side by side and parallel to each other. Inside a rolling station, each portion in one of the two successions is connected to a corresponding portion in the other, to form a second tobacco item hereinafter referred to as a "double cigarette." Each double cigarette consists of two cigarette portions separated by a double filter made integral with the two cigarette portions by a band, the central portion of which encloses the double filter, and each end portion of which encloses one end of a respective cigarette portion.
Still with reference to the above British patent, once formed, the double cigarettes are fed successively through a cutting station where they are cut transversely in half to form two successions of third tobacco items consisting of oppositely-oriented single cigarettes. That is, downstream from the cutting station, the cigarettes in each pair produced by cutting a respective double cigarette are arranged with their filters facing and substantially contacting each other.
According to the above British patent, the two successions of filter-tipped cigarettes are then fed to a turnover station where the cigarettes in one succession are turned over those in the other and into the gaps between respective adjacent pairs of cigarettes in said other succession, so as to produce a single succession of equioriented cigarettes, which are fed to the output of the filter assembly machine and directly or indirectly to the input of a packing machine.
Alternatively, as described in Italian Patent Application N. BO92A 000311, inside the turnover station, the cigarettes in one succession are turned over away from those in the other, so as to produce two separate successions of equioriented cigarettes, which are then fed to respective outputs of the filter assembly machine.
According to U.S. Pat. No. 5,135,008, the pitch or center distance between the tobacco items traveling along said path through the filter assembly machine undergoes only two successive reductions, following each of which the items are fed forward closer together. In actual fact, the items undergo three pitch reductions, one of which, however, is an inevitable consequence of the rolling operation, and is annulled when the original pitch is restored immediately after rolling.
On modern filter assembly machines, on which the tobacco items are fed transversely at relatively high speed, reductions in the pitch of the items involve not only relatively complex, high-cost handling operations, but also variations in speed resulting in relatively marked inertial forces capable of damaging the items.